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It's important to keep these points in mind when installing the valve.
Release date：2018/5/23
(1) direction and position
Many valves are directional, such as cut-off valves, throttle valves, pressure relief valves, check valves and so on. If reversed, it will affect the use effect and life (such as throttle valve), or do not function at all (such as pressure relief valve), and even cause danger (such as check valve). General valve, there is a direction sign on the valve body; if not, it should be correctly identified according to the working principle of the valve. The valve cavity of the shut-off valve is asymmetrical, and the fluid should let it pass from bottom to top through the valve mouth, so the fluid resistance is small (determined by the shape), and it opens the labor force (because the medium pressure is upward), the medium does not press packing after closing, and it is convenient for maintenance. This is the reason why the cut-off valve can not be safe and reverse. Other valves also have their own characteristics.
Valve installation position must be convenient for operation: even if installation is temporarily difficult, consider the long-term work of the operator. It is best to get the valve handwheel and chest together (usually 1.2 meters away from the operational floor), so that the opening and closing valves are more economical. The landing wheel should be upwards and not tilted, so as to avoid any awkward operation. Rely on the wall machine rely on the valve of the equipment, also need to leave the operator to stand room. To avoid operating on the sky, especially acids and alkalis, toxic substances, etc., otherwise it is very unsafe. The gate should not be reversed (i.e. the handwheel down), otherwise the medium will remain in the bonnet space for a long time. It will corrode the valve stem easily, and it is taboo for some technological requirements. It is very inconvenient to replace the filler at the same time. The gate valve should not be installed underground, otherwise it will corrode the exposed stem because of the humidity. Lift check valve should be installed to ensure that the disc is vertical, so that it can move up and down flexibly. Swing check valve should be installed to ensure that its pin is horizontal, so that it can be screwed up flexibly. The pressure relief valve should be erected vertically on the horizontal pipe and not tilted in all directions.
(2) construction work
Installation and construction must be careful and avoid hitting the valves made of brittle materials.
Before installation, the valve should be checked to check the specifications and types, identify the damage, especially for the stem. It also needs to rotate a few times to see if it is skewed, because the most easily inclined stem is in the transportation process. And remove the sundries in the valve.
When lifting the valve, the rope should not be attached to the handwheel or stem to avoid damaging these parts and should be tied to the flange.
For valves connected to the pipeline must be cleaned. Compressed air can be used to blow iron oxide, sand, slag and other debris. These impurities, not only easy to scratch the sealing surface of the valve, including large particles (such as welding slag), also can block small valves, make it invalid. When installing the valve, the sealing packing should be packed (line, aluminum or polytetrafluoroethylene), wrapped in the pipe thread, not in the valve, so as to avoid the valve's memory and affect the circulation of the medium.
When installing flanged valves, pay attention to tightening the bolts evenly and evenly. The valve flange and the pipe flange must be parallel and the clearance is reasonable, so as to avoid excessive pressure and even cracking. For brittle materials and low strength valves, particular attention should be paid to them. Valves that need to be welded with pipes should be welded first, and the closing parts should be fully opened before welding dies.
(3) protection measures
Some valves also need external protection, that is, heat preservation and cold insulation. Hot steam pipelines are sometimes added in the insulation layer. What kind of valves should be kept warm or cold should be determined according to production requirements.
In principle, if the medium to reduce the temperature of the valve in the valve is too much, it will affect the production efficiency or the freezing of the valve, it is necessary to keep heat and even heat. When the valve is exposed, it is necessary to keep cold when it is bad for production or cause frost. Thermal insulation materials include asbestos, slag cotton, glass wool, perlite, diatomite, vermiculite, etc. cold insulation materials include cork, perlite, foam, plastic and so on.
(4) bypass and instrument
In addition to the necessary protection facilities, some valves must have bypass and meters. A bypass was installed. It is easy to repair the trap valve. Other valves, also have the installation of bypass. Whether bypass is installed depends on valve condition, importance and production requirements.
(5) replacement of packing
Stock valve, some filler is not good enough, some of which are inconsistent with the use of media, which requires replacement of fillers.
The production plant of the valve can not consider the different medium of a thousand million units, and the filling letter is always filled with common root, but the filling must be adapted to the medium.
When the filler is replaced, a circle is pressed into the ground. It is advisable for each lap to be 45 degrees and 180 times to the circle. The height of the packing should be taken into account the rest of the press cover. At present, the depth of the packing chamber at the lower part of the cap is also required. This depth can generally be 10-20% of the total depth of the packing chamber. For high required valves, the joint angle is 30 degrees. The joint between the circle and the circle is 120 degrees apart. In addition to the above packing, according to the specific conditions, the rubber O ring (natural rubber, less than 60 degrees Celsius, under 80 degrees centigrade and under 150 degrees centigrade corrosion medium for fluorine rubber), three superimposed
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Many valves are directional, such as cut-off valves, throttle valves, pressure relief valves, check valves and so on. If reversed, it will affect the use effect and life (such as throttle valve), or do not function at all (such as pressure relief valve), and even cause danger (such as check valve). General valve, there is a direction sign on the valve body; if not, it should be correctly identified according to the working principle of the valve. The valve cavity of the shut-off valve is asymmetrical, and the fluid should let it pass from bottom to top through the valve mouth, so the fluid resistance is small (determined by the shape), and it opens the labor force (because the medium pressure is upward), the medium does not press packing after closing, and it is convenient for maintenance. This is the reason why the cut-off valve can not be safe and reverse. Other valves also have their own characteristics.
Valve installation position must be convenient for operation: even if installation is temporarily difficult, consider the long-term work of the operator. It is best to get the valve handwheel and chest together (usually 1.2 meters away from the operational floor), so that the opening and closing valves are more economical. The landing wheel should be upwards and not tilted, so as to avoid any awkward operation. Rely on the wall machine rely on the valve of the equipment, also need to leave the operator to stand room. To avoid operating on the sky, especially acids and alkalis, toxic substances, etc., otherwise it is very unsafe. The gate should not be reversed (i.e. the handwheel down), otherwise the medium will remain in the bonnet space for a long time. It will corrode the valve stem easily, and it is taboo for some technological requirements. It is very inconvenient to replace the filler at the same time. The gate valve should not be installed underground, otherwise it will corrode the exposed stem because of the humidity. Lift check valve should be installed to ensure that the disc is vertical, so that it can move up and down flexibly. Swing check valve should be installed to ensure that its pin is horizontal, so that it can be screwed up flexibly. The pressure relief valve should be erected vertically on the horizontal pipe and not tilted in all directions.
(2) construction work
Installation and construction must be careful and avoid hitting the valves made of brittle materials.
Before installation, the valve should be checked to check the specifications and types, identify the damage, especially for the stem. It also needs to rotate a few times to see if it is skewed, because the most easily inclined stem is in the transportation process. And remove the sundries in the valve.
When lifting the valve, the rope should not be attached to the handwheel or stem to avoid damaging these parts and should be tied to the flange.
For valves connected to the pipeline must be cleaned. Compressed air can be used to blow iron oxide, sand, slag and other debris. These impurities, not only easy to scratch the sealing surface of the valve, including large particles (such as welding slag), also can block small valves, make it invalid. When installing the valve, the sealing packing should be packed (line, aluminum or polytetrafluoroethylene), wrapped in the pipe thread, not in the valve, so as to avoid the valve's memory and affect the circulation of the medium.
When installing flanged valves, pay attention to tightening the bolts evenly and evenly. The valve flange and the pipe flange must be parallel and the clearance is reasonable, so as to avoid excessive pressure and even cracking. For brittle materials and low strength valves, particular attention should be paid to them. Valves that need to be welded with pipes should be welded first, and the closing parts should be fully opened before welding dies.
(3) protection measures
Some valves also need external protection, that is, heat preservation and cold insulation. Hot steam pipelines are sometimes added in the insulation layer. What kind of valves should be kept warm or cold should be determined according to production requirements.
In principle, if the medium to reduce the temperature of the valve in the valve is too much, it will affect the production efficiency or the freezing of the valve, it is necessary to keep heat and even heat. When the valve is exposed, it is necessary to keep cold when it is bad for production or cause frost. Thermal insulation materials include asbestos, slag cotton, glass wool, perlite, diatomite, vermiculite, etc. cold insulation materials include cork, perlite, foam, plastic and so on.
(4) bypass and instrument
In addition to the necessary protection facilities, some valves must have bypass and meters. A bypass was installed. It is easy to repair the trap valve. Other valves, also have the installation of bypass. Whether bypass is installed depends on valve condition, importance and production requirements.
(5) replacement of packing
Stock valve, some filler is not good enough, some of which are inconsistent with the use of media, which requires replacement of fillers.
The production plant of the valve can not consider the different medium of a thousand million units, and the filling letter is always filled with common root, but the filling must be adapted to the medium.
When the filler is replaced, a circle is pressed into the ground. It is advisable for each lap to be 45 degrees and 180 times to the circle. The height of the packing should be taken into account the rest of the press cover. At present, the depth of the packing chamber at the lower part of the cap is also required. This depth can generally be 10-20% of the total depth of the packing chamber. For high required valves, the joint angle is 30 degrees. The joint between the circle and the circle is 120 degrees apart. In addition to the above packing, according to the specific conditions, the rubber O ring (natural rubber, less than 60 degrees Celsius, under 80 degrees centigrade and under 150 degrees centigrade corrosion medium for fluorine rubber), three superimposed
